REUTERS - Ethiopia attacked rebel bases inside neighbouring Eritrea on Thursday, accusing its arch-foe of training fighters who have staged raids, including a January attack that killed five Western tourists.

It was the first attack by Ethiopian troops inside Eritrea since the end of a 1998-2000 war that killed 70,000 people and still festers, because the frontier dispute that ignited the conflict remains unresolved.

Ethiopia routinely accuses Asmara of supporting Ethiopian separatist groups. It blamed an Afar rebel movement for the kidnapping of Westerners in its northern Afar region in 2007, and again for the attack in the same area in January.

"Our national defence force has today taken measures against military posts inside Eritrea in which subversive and anti-peace elements were trained," government spokesman Shimeles Kemal told reporters.

Gunmen killed two Germans, two Hungarians and an Austrian in a dawn attack on a group of tourists in the remote Afar region on Jan. 17, and seized two Germans and two Ethiopians.

A rebel group in the Afar region said last week had freed the two German tourists, although there has been no official confirmation of the release.

"These groups are operating in the Afar area. We know for certain that the Eritrean government harbours, supports, trains and deploys subversive groups that occasionally launch attacks on civilian and infrastructure targets inside Ethiopia," he said.

Shimeles said Ethiopian soldiers attacked three places - Ramid, Gelahbe and Gimbi - 16 km (10 miles) inside southeastern Eritrea. "We will continue our measures as long as they remain a launching pad for similar attacks," he said.